1. Field of the Invention
The present invention relates to a solid-state imaging device, its driving method, and a camera system. In particular, the invention relates to an X-Y address solid-state imaging device having an electronic shutter function, its driving method, and a camera system using such a solid-state imaging device.
2. Description of the Related Art
In X-Y address imaging devices having an electronic shutter function, the shutter is released line by line, which is in contrast to the case of CCD (charge coupled device) imaging devices having an electronic shutter function. In CCD imaging devices, it is not necessary to release the shutter line by line because signal charges of respective pixels are read into a vertical transfer section at one time. In contrast, in X-Y address imaging devices, the shutter is released line by line because signals of respective pixels are read out on a line-by-line basis.
Therefore, conventional X-Y address imaging devices are provided with an electronic shutter scanning circuit in a vertical scanning section. However, since the vertical scanning section scans the lines every 1H (H: horizontal scanning period), settable exposure times (i.e., shutter speeds) are limited to integral multiples of 1H; that is, an electronic shutter having a unit exposure time that is shorter than 1H has not been realized yet.